Production and/or separation of nonionic surface active agents



nited States Patent FPRODUCTIO'N-AND/ORSEPARATION'OFNON- IIONIC SURFACE-ACTIVEYAGENTS DennisHe'nryDesty and Charles Leslie Arthur Harbourn,

This invention relates to "animproved' process for-the production and/or separation of 'non-ionicsurface*active agents.

'It is well known that by the condensation of ethylene oxide in thepresenCeof-fatty acids, resin acid,--alcohols,,

alkylated phenols or -m'ercaptans, products having *an ethylene oxide chain are obtained which are of considerable utilit-y as surface active agents. The length of the ethyleneoxidechain is an important factor in'determining the .surface active characteristics of the compound-in which "it is-contained. Thusaccording to length ofthe ethylene oxide chain, compounds of =a-particular type, diiferingonlyin respect'of this-chain-length, find primary utilityasfoaming agents, dispersing agents, wetting agents,

emulsifying agents, solutizers or as-detergents.

It is aacharacteristic of thecondensation reaction by which these surface active agents areformed that it "is not possible to obtain with ease a 'single'compound as product of said reaction and, in general, the product obtained consists of a mixture of compounds, said-compounds differing onefrom another in respect of-the length of the ethylene oxide chain. Thus, iii-general, bycommercially feasible. processes, the surface active agent obtained, While containing compounds ofpre-eminence in utility for atparticular function, will contain substantial proportions of compoundshavinggreater utility for a 'di'tferent' function.

It isa'n object of'the invention toprovide aprocess for the fractionation of nonvi'onic surface active: agents comprising mixtures of surface active compounds, to obtain fractions differing in surface active'characteristics.

It is another object to provide a'p r'ocess for theproduction of non-ionic active agents,- having a desired surface active characteristic, in improved yields. M

According to thehpresent invention there is -provided a processvvhich cornprisesadding a1precipitati'ng agent .to a solution of a non-ionic surface active agent in "an organic solvent, said surface "active agent comprising a mixture "of'sur'face active compounds having, in the molecule, a chain of ethylene oxide. groups, the surface activeager'it' being only partiallysoluble in 'saidprcipitap in gent an'd said-precipitating agent being-a l'quid \vhi'ch i :mi'scible"vv' h saidaanvenewhere 'p'art'of said-surface ative agent istlirovvn oufif-soltitibnfandthfieafter recovering the precipitated; fraction.

When the non-ionic surface active agent comprises a mixture of surface active compounds having, in the molecule, ethylene oxide chains diife'ring length, the fraction precipitated will contain "an increased portion of compounds having-relatively long ethylene oxide -ehains and the remainingsolution will-contaiifi 'a'n increased proportion of compounds havinga relatively short ethylene oxide chain. 7 I N If desired the process maybe'operatedjtofgiveaipluralitybfprecipitated fractions, for eampleby progressive additions of the "precipitatingliquid arty iiib'dific'a- 2,814,613 Patented ov. -26 1957 tion of the reaction conditions, as'by progressvely'decreasing'the temperature. Operating in the manner described, itis possible; to obtain two or more fractions froma mixed non-ionic surface active agent, each of the said fractions being ofparticular utility as a wetting agent or as 'an emulsifying agent or as a detergent.

According to another aspect of the-presentinvention there is provided a process which comprises reacting ethylene oxide with a "suitable-organic compound whereby a non-ionic active agent is formed comprising a mixtureof surface active compounds having, in'th'e'jmolecule, ethylene oxide chains of'difiering lengths and thereafter,

in the'presence of a solvent therefor, added to the reac. {tion mixture or'to the reaction product, fractionallypre- *cipitating part "of the product, comprising compounds having an ethylene oxide chain of at least the desired length, by'the addition of afp'rec'ipita'ting agent compris- 'iii'g' a liquid 'wh'ich is misciblewith said solvent and in "which said agent is only partly soluble and thereafter "rcyc'lingat least part of the 'rem'ainder'of the'product,

comprising compounds lia vijng a relatively short ethylene oxide chain, "to "the reaction'm xture comprising ethylene oxide and said organic 'compound. I r I I Suitable organic compoundsfor "reaction with ethylene oxide to"form "surface active agents are fatty acids, resin acids, alcohols, alkylatdphenol s and mercaptans. L

Suitable solvents for the non-ionic surface active agents are low hidleciilar' vveight aliphatic alcohols and retai er,

preferably having -1=3 carbon orn s/moleculeff or example, ethanol and acetone; aromatic'hydrocarbons,for e'xa'm'p'le, beniene 'and'to-lfiene; napiithe nesffor example cyclopenta'ne aridcyclohe'xar'ie and chlorinated hydrocarbo'ns, "for example, carbon tetrachloride and chloroform. Apreferred solvent is cy'clohe'xane. I

suitableprecipitating agents are saturated aliphatic hydrocarbbiis, 'for example, normal-'pent'ane', iso hexane, normal-hexane, 'isopentane, normal-heptar'ie, iso 'octaiie. A preferred material is isohexarie.

It is'also possihlqby'the process of the present invention, to-eifect a separati'onbf mixtures of compo'uhds containing'anethylene oxide chain,bas 'ed on dissimilari'tie's in molecular structure other than 'e'th'yle'ne'oxide chain length. Thus, forexample, it is possible in accordance with the-process of the invention'to fractiona'te mixtures containing compounds in which there are differences in thestnlcture of-the gro'upasso'ci'ated with the ethylene OXldfifChfiiIlOI" in the manner of attachment of said group to said chain. The operation of a' process in'this'manner lies within the scope of the invention.

Fractions of non-ionic surface active agents, precipitated in the mannerhereind'es'cribed are very suitable for use'as feedstocks to 'a process for the 'f'ormationof solid non-ionic surface active agents by reaction with urea as described in British patent application Serial N 697,315. g, v

The invention'is illustrated but in no Way limited by the following examples. I, p p Lissapol NXA"is a surface active agent having the formula R A O (CH H O -),;CH CH5 OH ivhfe R is an alien grouphaviiig, "an the average, car Ben atoms; fA'is a benzene ring; and iii'vvhi ch the value of it varis,jb'ii1gapproximately '12. Lis s'a p'ol i's'a'rgister'd trademark.

Example 1 proximately IOgiaiiisBf surface a'eave agent had'beii thrown out of solution. The lower layer consisting of the precipitated liquid surface active agent was removed, being referred to hereinafter as fraction 1.

The addition of iso-octane to the remaining solution was continued until a further grams of surface active agent had been thrown out of solution. The lower layer consisting of the precipitated liquid surface active agent was removed, being referred to hereinafter as fraction 2.

The remaining mixture of surface active agent, cyclohexane and iso-octane was distilled to remove cyclohexane and iso-octane overhead, the residual surface active agent constituting fraction 3.

Example 2 This example illustrates the difference in properties of the feedstock, that is, untreated Lissapol NXA and fractions 1, 2 and 3. In each case the liquid surface active agent was convertedto solid form by the process described in the specification filed in respect of British patent application Serial No. 697,315.

(a) 10 grams of Lissapol NXA, 100 ml. of normal pentane and 1 ml. of methanol were mixed and thereafter, grams of urea added. The mixture was stirred for 1 hour, allowed to stand for 48 hours and then filtered. The solid product, after evaporation of residual solvent, was a dark brown, slightly tacky powder.

(b) 10 grams of fraction 1, 100 ml. of normal pentane and 1 ml. of methanol were mixed and thereafter, 20

grams of urea added. The mixture was stirred for "minutes, allowed to stand for 2 hours, by which time a :satisfactory product had formed and then filtered. The :solid product, after evaporation of residual solvent, was

a fine, light brown free-flowing powder.

(c) 10 grams of fraction 2, 100 m1. of normal pentane and 1 ml. of methanol were mixed and thereafter, 20 grams of urea added. The mixture was stirred for 30 minutes. After standing for 2 hours the adduct was not yet in a conditionfor filtration. After 12 hours standing a satisfactory adduct had been formed. This was filtered off and residual solvent evaporated off. The product was a fine, light brown free-flowing powder.

(b) 10 grams of fraction 3, 100 ml. of normal pentane and 1 ml. of methanol were mixed and thereafter, 20 grams of urea added. The mixture was found to be unsuitable for the formation of a solid adduct in the form of a free-flowing powder.

The above experiments clearly show that fractions 1, 2 and 3 differ in properties from' the feedstock and from each other. Furthermore the precipitated fractions, fractions 1 and 2 are superior to the feedstock and to fraction 3 in the ease of formation of solid adducts with urea and, in respect of colour of product.

We claim:

1. A process for the fractionation of a non-ionic surface active agent containing a mixture of surface active poly ethyl oxy condensation products of compoundsselected from the group consisting of fatty acids, resin acids, alcohols, alkylated phenols and mercaptans to obtain fractions differing in surface-active characteristics, which comprises adding a saturated aliphatic hydrocarbon as a precipitating agent to a solution of saidsurface active agent in an organic solvent selected from the group consisting of low molecular weight alcohols, low molecular weight ketones, aromatic hydrocarbons, naphthenes and chlorinated hydrocarbons, said surface active agent being only partially soluble in saidprecipitating agent and said precipitating agent being a liquid which is miscible with said solvent, whereby part of said surface active agent is thrown out of solution to form a precipitated fraction and thereafter recovering said fraction.

2. A process for the production of a non-ionic surface active agent which comprises reacting ethylene oxide with an organic compound selected from the group consisting of fatty acids, resinacids alcohols, alkylated phenols. and

mercaptans to form a non-ionic surface active agent therewith containing a mixture of surface active compounds having, in the molecule, ethylene oxide chains of differing lengths and thereafter, in the presence of an organic solvent selected from the group consisting of low molecular weight alcohols, low molecular weight ketones, aromatic hydrocarbons, naphthenes and chlorinated hydrocarbons, fractionally precipitating part of the product containing compounds having an ethylene oxide chain of at least the desired length by the addition of an unsaturated aliphatic hydrocarbon as a liquid precipitating agent which is miscible with said solvent and in which said agent is only partly soluble, and thereafter recycling at least part of the remainder of the product containing compounds having a relatively short ethylene oxide chain to the reaction mixture comprising ethylene oxide and said organic compound.

3. A process for the production of a non-ionic surface active agent which comprises reacting ethylene oxide with an organic compound selected from the group consisting of fatty acids, resin acids, alcohols, alkylated phenols and mercaptans to form a non-ionic surface active agent therewith, containing a mixture of surface active compounds having, in the molecule, ethylene oxide chains of differing lengths and thereafter, in the presence of an organic solvent selected from the group consisting of low molecular weight alcohols, low molecular weight ketones, aromatic hydrocarbons, naphthenes and chlorinated hydrocarbons, fractionally precipitating part of the product containing compounds having an ethylene oxide chain of at least the desired length by the addition of an unsaturated aliphatic hydrocarbon as a liquid precipitating agent which is miscible with said solvent and in which said agent is only partly soluble, thereafter subjecting the solution remaining after removal of the precipitated fraction to distillation for the removal of the organic solvent and precipitating agent, and recycling the surface active agent to the reaction mixture comprising ethylene oxide and said organic compound.

4. A process as specified in claim 1 in which the precipitating agent is added in a plurality of stages, a precipitated fraction being recovered at each stage.

5. A process as specified in claim 1 in which the solution remaining after removal of the precipitated fraction is subjected to distillation, for the removal of organic solvent and precipitating agent, and a residue fraction of non-ionic surface active agent recovered.

6. A process as specified in claim 1 in which the organic solvent is cyclohexane.

7. A process as specified in claim 1 in which the precipitating agent is iso-hexane.

8. A process as specified in claim 3 in which the organic solvent is cyclohexane.

9. A process as specified in claim 3 in which the precipitating agent is iso-hexane.

10. ,A process as defined in claim 1, in which each of the compounds forming the mixture of non-ionic surfaceactive compounds is a compound having the formula R-A-0-(CH CH O-) CH CH 0I-I wherein R is an alkyl group and A is a phenylene, group, R in the mixture having an average of 8 carbon atoms and A in the mixture having an average value of 12.

References Cited in the file of this patent UNITED, STATES PATENTS 2,118,454 Schaafsma May 24, 1938 2,226,119 De Groote Dec. 24, 1940 2,233,382 De Groote Feb. 25, 1941 2,674,619 Lunstead Apr. 6, 1954 OTHER REFERENCES Chem. Abstracts, vol. 46, pp. 89334 (1952). The Use of Solvents, MacArdle, D. Van Nostrand Co., New York (1925) pages 151-155 only. 

1. A PROCESS FOR THE FRACTIONATION OF A NON-IONIC SURFACE ACTIVE AGENT CONTAINING A MIXTURE OF SURFACE ACTIVE POLY ETHYL OXY CONDENSATION PRODUCTS OF COMPOUNDS SELECTED FROM THE GROUP CONSISTING OF FATTY ACIDS, RESIN ACIDS, ALCOHOLS, ALKYLATED PHENOLS AND MERCAPTANS TO OBTAIN FRACTIONS DIFFERING IN SURFACE-ACTIVE CHARACTERISTICS, WHICH COMPRISES ADDING A SATURATED ALIPHATIC HYDROCARBON AS A PRECIPITATING AGENT TO A SOLUTION OF SAID SURFACE ACTIVE AGENT IN AN ORGANIC SOLVENT SELECTED FROM THE GROUP CONSISTING OF LOW MOLECULAR WEIGHT ALCOHOLS, LOW MOLECULAR WEIGHT KETONES, AROMATIC HYDROCARBONS, NAPHTHENES AND CHLORINATED HYDROCARBONS, SAID SURFACE ACTIVE AGENT BEING ONLY PARTIALLY SOLUBLE IN SAID PRECIPITATING AGENT AND SAID PRECIPITATING AGENT BEING A LIQUID WHICH MISCIBLE WITHH SAID SOLVENT, WHEREBY PART OF SAID SURFACE ACTIVE AGENT IS THROWN OUT OF SOLUTION TO FORM A PRECIPITATED FRACTION AND THEREAFTER RECOVERING SAID FRACTION. 